All About Water

The xylem and phloem are the two kinds of tissues that transport water and other nutrients within plants. The xylem carries water up through the plant. The phloem transports nutrients, most notably glucose, down throughout the plant.

Xylem and Phloem: The Xylem

In Classical Greek, “xylem” translates to “wood.” This makes sense, as the most common xylem tissue is wood. The xylem supply all of the parts of a plant with water by transporting water up through the plant. Xylem are long tubes called vessels. They pump water from the roots up, replacing the water that plants lose to transpiration and photosynthesis.

Xylem and Phloem: How the Xylem Transport Water

Plants depend on xylem to replace the water that evaporates off of their leaves. The xylem can transport their sap through transpirational pull. In transpirational pull, water transpires, or evaporates, off of plant surfaces into the atmosphere. As transpiration pulls water out of the plant, the water tension within the plant pulls water from the plant’s roots and soil back into the leaves. This water tension is strong enough to lift water hundreds of meters above the ground into the highest branches of trees. However, for transpirational pull to work, the xylem vessels must be very compact in diameter, as this compactness maximizes pressure.

Xylem and Phloem: Other Ways That the Xylem Transport Water

The xylem can also pull water and nutrients up through the plant via root pressure. Through osmosis, plants absorb water into their roots. This osmosis then forces sap up the xylem and into the leaves. The xylem are also aided by capillary action, the force by which water adheres to the surface of xylem pipes. This capillary action balances gravity.

Xylem and Phloem: How the Phloem Work

Phloem is the second transporting tissue in vascular plants. The phloem carry nutrients, most notably glucose, down throughout the plant. Like “xylem,” “phloem” derives from Ancient Greek. “Phloem” translates to “bar,” which makes sense, as phloem is the innermost layer of bark in trees. Phloem transport the nutrients that plants produce in photosynthesis. The phloem’s transportation is called translocation. Translocation moves the phloem’s sugar-rich sap from sugar sources to sugar sinks. Plants generally store their sugars in their roots, and the phloem transports sugar from the roots to the growing areas in the plant, the sugar sink.

Differences Between the Xylem and Phloem

The xylem and phloem both transport vital commodities through plants. However, the xylem and phloem differ in several ways. While the xylem transport mostly water, the phloem transport nutrients, especially glucose. The xylem are made up of dead cells, while the phloem are made up of living cells. Xylem only transport sap upward, while the phloem are multidirectional—they move sugars wherever they’re needed. To work, the xylem rely on water tension, while the phloem rely on translocation.

Water Clarity

When we think of oceans and lakes, we think of sparkling blue waters. However, upon closer investigation, we see that water is clear.  The reason why water is clear is that it is made up entirely of oxygen and hydrogen.  Because both of these elements are gases, their electrons are unable to absorb or reflect visible light. In fact, water refracts or changes the direction of light. For example, when a T-shirt is soaked with water, it refracts away light, making the object appear darker.  This is why absorbed water darkens material, and why water is clear.

Why Water Is Clear If Ocean and Lake Water Looks Colored

We know how and why water is clear, so it probably doesn’t make immediate sense to us that while a small amount of water is clear, lakes and oceans appear to be blue. The reason for this is that water does not absorb much light, but when it does absorb light, it absorbs red, orange and yellow light.  As a result, it reflects back the shorter blue wavelengths to observers.

Why Water Is Clear: Misleading Opacity

Large bodies of water do not always appear blue.  Many rivers can appear brown, green or even gray. These appearances can be explained by the number of dissolved or suspended particles present in water, and the depth of the water. Both particles and water depth influence how light is reflected or refracted to the observer.  Color variants arise depending on the following circumstances:

• Gray water is generally water that has been stained by runoff from parking lots, buildings and roads in urban areas.
• Brown water is colored by dissolved organic materials like plants and animals.  It is usually found in forests and wetlands.
• Green water is usually stained by suspended particles of living materials, like algae or other microscopic plants.

Why Water Is Clear: Checking for Clarity

If water is clear, there is a much better chance that it is clean.  This is why we must check whether water is turbid or hazy.  We can check water clarify with a Secchi Disk.  This instrument is a black-and-white circular plastic plate that can be lowered into water.  To use a Secchi Disk, first lower it into the water. Stop lowering it when you can’t see it anymore. Next, note the depth (in meters) off of the calibrated line. Then raise the disk back up to where it reappears, again noting the depth off of the calibrated line. Finally, add these two noted depths and divide them by two. This final value can help you gauge water’s clarity. Be sure to compare this value on a weekly basis with measurements at the same lake.

What Is Water?

The chemical formula for water is H₂O. This formula means that one molecule of water is made up of to two hydrogen atoms bonded with one oxygen atom. Oxygen is a negatively charged atom and hydrogen is positively charged, but when the electrons of these atoms combine to form a water molecule, the molecule’s charge is not evenly distributed: the molecule has a slight negative charge on its oxygen end and a slight positive on its hydrogen end. Because of this, water molecules are polar. This polarity causes water molecules to be electrostatically attracted to other water molecules, and also allows water molecules to dissolve other molecules.

What is Water: Polarity’s Effects

Polarity makes water molecules special. For instance, it causes water’s solid form, ice, to float atop its liquid form, water—and unusual chemical property. This happens because water molecules’ hydrogen bonds repulse other water molecules’ hydrogen bonds, which makes the solid water molecules be spaced further apart from each other than they were as liquid water molecules. This causes ice to be less dense than water, thereby causing ice to float.

What Is Water: Other Unusual Properties

When we wonder what is water, need to understand water’s also possesses some other interesting physical properties.

• Water has strong surface tension, high heat of vaporization, and high specific heat.
• Water dissolves more substances than any other liquid, and has therefore been nicknamed “the universal solvent.”
• Water is the only chemical compound on Earth’s surface that is naturally present as liquid, gas and solid.

What is Water: Water Is Necessary for Life

All of life’s biochemical reactions rely upon liquid water to occur. Without water, the world as we know it would not exist. The world’s temperature systems would be wildly different, chemical reactions would not occur, and organisms would not be able to maintain their cell membranes. In chemical reactions, water pushes non-polar compounds together. This hydrophobia is the basis for the creation and maintenance of cell membranes, which are necessary for all living organisms. Additionally, only water can bend enzymes into the proper shape for catalyzing the chemical reactions that we need to stay alive. What is water? Necessary for life. Us folks of Operation Hydros understand how important water is, and that’s why we’re fighting so hard to conserve it.

Why does water boil? The answer to the question “Why does water boil” is important knowledge for everyone, as water is part of the basis of human life and provides many health benefits. Boiling water has a number of uses, includingboiling to purify water, sterilizing medical tools, cooking, and as a starting material or solvent in chemical reactions. The boiling point of water and the process of boiling itself is determined by various chemical properties of the substance.

Why Does Water Boil: Boiling Water for Food Preparation

One place to begin investigation of the question “why does water boil” is to survey the most familiar usage of boiling water: food preparation. A variety of simple foods including spaghetti and hard boiled eggs can be prepared simply by placing them in a pot of boiling water. One Food Network show even has the tongue-in-cheek title “How to Boil Water.” With a subject this familiar, a few myths and sayings have naturally arisen. “A watched pot never boils,” says one popular expression. Of course, this is not technically true, an intense gaze having absolutely no effect on the boiling point of water.

Does adding salt to water change anything besides taste?

Something that does affect the boiling point of water, however, is the old tradition of throwing a pinch of salt in the pot. Adding salt to water will raise the boiling point of the water due to the reduction in vapor pressure. This means that the water will boil more slowly, which can be an advantage when trying to hard boil the perfect egg. For an in depth analysis on these effects, referring to Volker Thomsen’s article “The Boiling Point of Water” written for The Physics Teacher may be helpful, or simply just continue reading.

Why Does Water Boil: The Chemistry

When asking why does water boil, people may come across such phrases as “vapor pressure,” “atmospheric pressure,” and “heat of vaporization.” While the boiling point of water is listed as 100 degrees Celsius, the truth is that the boiling point given in the literature is that for standard pressure, approximated as 1 atm.

Why Does Water Boil: More Information on Pressure

But why does water boil at different temperatures depending on the pressure? The short answer is that in order for water to boil, the vapor pressure must be equal to the atmospheric pressure, as molecules are inclined to move from a high pressure to a lower pressure. Though the transition of water from a liquid phase to a gas phase is constantly occurring (think of evaporation), when the vapor pressure of the liquid is lower than the atmospheric pressure, the equilibrium of the process is in favor of the return of the molecule to the liquid phase, or condensation. Boiling, then, occurs when equilibrium favors transition to the gas phase over the vapor phase.

Why Does Water Boil: Boiling Points

When looking at the question of “why does water boil,” it may be interesting to note that water has a higher boiling point and thus takes a longer time to boil than many other liquids such as ethers. Water is made up of a bond of two hydrogen bonds to an oxygen molecule, and as a relatively highly electronegative molecule, oxygen attracts electrons more than hydrogen, creating a partial negative charge on the oxygen molecule and a partial positive on each of the hydrogen molecules. These partial charges mean that the molecule is polar. When this polar molecule is close to other molecules of its kind, hydrogen-hydrogen bonding occurs. These weak bonds may break easily, but breaking these bonds in order to bring all of the molecules into vapor phase requires some additional energy.

Why Does Water Boil: Hydrogen Bonding

The phenomenon of hydrogen bonding is a large contributing factor to the high specific heat of water, 4.18 J/gK. The specific heat is related to how rapidly water can be brought to a boil because it is a measure of how much energy it takes to raise one gram of the substance by one degree Celsius. In more familiar units, it takes one calorie of energy to raise one gram of water by one degree Celsius. Of course, this is the scientific calorie, which is 1/1000 of the food calorie, so just one food calorie could raise one gram (or mL, density of water being 1 g/mL) of water by 1,000 degrees Celsius: good news for cells, which need the energy for metabolism.

Are you wondering what to do when you see black flecks in your filtered water? Are they harmful to you or your family? Here are some answers.

What are the black flecks that I see in my water?

The black flecks are bits of carbon from your filter. They are non-toxic as well as tasteless. In fact, activated carbon has been used as an antidote to poison in hospitals. However, it is still advisable to keep the filter out of reach of children.

How can I get rid of the black flecks?

The accompanying instructions for most filters advise that you first soak the filter itself in water before use. Then, after putting the filter to use two times, the flecks should disappear. You can also take the added step of shaking the filter under water to encourage the release of the flecks using it for your daily filtration.

Though the home filtration systems on the market require little maintenance, you should properly maintain your water filter to ensure good quality water. Wash the top portion of your filter out once in a while or more often if you use it heavily, so that the activated carbon specks do not collect. Don’t forget to wash the pitcher itself.

Replace your filter regularly

Generally you should notice only a few blackflecks coming out after thoroughly soaking the water filter. If large amounts are being discharged, the filter might have a slight defect in its seal, and you should consider replacing it. Certainly if the filter is past its prime, you will see a higher than normal concentration of black flecks, and you should simply replace it. Follow the suggested replacement schedule in the instruction booklet.

What is the function of the black flecks?

Most home-based water filter systems use an activated carbon water filter method. Activated carbon is the most powerful and simple way to eliminate the variety of impurities, such as odors, chlorine, and chemicals in the water supply, such as pesticides and herbicides. Activated carbon–the black flecks that you see–both absorbs the impurities and makes your water more alkaline.